In a contractional syntectonic structure, an inverse line to the area–depth markers of the growth section is a good first approximation to the best-fit line defined by the area–depth markers of the pregrowth section and thus, to the true detachment depth and displacement of a structure. The validity of this concept was tested through a series of case studies and fault-propagation fold models. Case studies suggest that (1) the inverse line tends to underestimate the detachment depth and (2) there is a direct relationship between the proxy displacement (D2) given by the inverse line and the true displacement of the structure (D1) through the power-law function D1 = 0.76 × D20.61. Additionally, models indicate that the inverse line gives good predictions of detachment and displacement at high sediment-to-uplift ratios for models with low displacements and vice versa. Thus, two possible solutions are proposed to estimate detachments and displacements directly from the growth section: (1) to use the function derived from the case studies to obtain D1 from D2 or (2) to use the D2 value given by the inverse line and an estimate of the sediment-to-uplift ratio to obtain a possible D1/D2 ratio from which to approximate D1. These workflows could help structural and exploration geologists working in areas where syntectonic sequences are observed, but in which seismic data is of poor quality or incomplete at depth.